Resonant pivoting surface with inertially coupled activation

• US 20040007069A1
• Filed: 05/19/2003
• Published: 01/15/2004
• Est. Priority Date: 07/08/2002
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Turner, Arthur Monroe, Heaton, Mark W., Dewa, Andrew S.
• Granted Patent: US 6,964,196 B2
• Time in Patent Office: Days
• US Class Current: 73/580
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129

Abstract

A system and method for providing resonant movement about a first axis. A functional surface supported by a first pair of torsional hinges is driven into resonant oscillations about the first axis by inertially coupling energy through the first pair of torsional hinges. The resonant movement may be moved orthogonally on the target area by a gimbals portion of the functional surface pivoting about a second axis according to one embodiment. The resonant oscillation of the functional surface is monitored to detect changes in frequency due to mass changes of the functional surface.

Claims

1. Apparatus for providing a resonant movement about a first axis, said apparatus comprising:

a device integrally formed from a single piece of material comprising a functional surface portion, and a first pair of torsional hinges attached to said functional surface portion and extending to a support portion for pivoting said functional surface portion about said first axis; and

a driver circuit for generating vibrational energy in said support portion and wherein said vibrational energy is inertially coupled from said support portion through said first pair of torsional hinges to said functional surface portion such that said functional surface portion oscillates about said first pair of torsional hinges at a resonant frequency, and wherein said resonant frequency changes with changes in the mass of said functional surface portion.

2. The apparatus of claim 1 further comprising a support structure and wherein said support portion of said device is a frame member having a first portion thereof attached to said support structure.

3. The apparatus of claim 1 wherein said support portion comprises first and second support anchors attached to said support structure.

4. The apparatus of claim 1 wherein said driver circuit comprises at least one electrostatic plate spaced a selected distance from said support portion and an alternating voltage source connected between said at least one electrostatic plate and said support portion and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

5. The apparatus of claim 1 wherein said driver circuit comprises at least one portion of piezoelectric material having a first end and a second end, said portion of piezoelectric material bonded to said support portion and an alternating voltage source connected between said first end and said second end of said portion of piezoelectric material, and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

6. The apparatus of claim 1 wherein said driver circuit comprises a pair of electromagnetic coils, one each of said pair located on each side of said first axis and spaced from said functional surface portion, and an alternating voltage source connected across said pair of coils, and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

7. The apparatus of claim 1 wherein said support portion of said device comprises a support frame and a gimbals portion supported by a second pair of torsional hinges located at substantially a right angle with said first pair of hinges and extending to said support frame, said gimbals portion pivoting about a second axis orthogonal to said first axis.

8. The apparatus of claim 7 wherein said driver circuit comprises at least one electrostatic plate spaced a selected distance from said support frame and an alternating voltage source connected between said at least one electrostatic plate and said support frame and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

9. The apparatus of claim 7 wherein said driver circuit comprises at least one portion of piezoelectric material having a first end and a second end, said portion of piezoelectric material bonded to said support frame and an alternating voltage source connected between said first end and said second end of said portion of piezoelectric material, and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

10. The apparatus of claim 7 wherein said driver circuit comprises

a pair of magnets, one each of said pair of magnets located on said functional surface portion and on each side of said first axis;

a pair of electromagnetic coils, one each of said pair of coils located on each side of said first axis and spaced from said functional surface portion; and

an alternating voltage source connected across said pair of coils, said frequency of said alternating voltage source is substantially at said resonant frequency.

11. The apparatus of claim 7, and further comprising a pair of electromagnetic coils, one each of said pair located on each side of said second axis and spaced from said gimbals portion, and a voltage source connected across said pair of coils for selectively positioning said resonant functional surface in a direction orthogonal to said movement.

12. The apparatus of claim 1 wherein said support portion of said functional surface device comprises a gimbals portion supported by a second pair of torsional hinges located at substantially right angles with said first pair of hinges and said second pair of torsional hinges extending one each to one of a pair of support anchors, said second pair of torsional hinges for pivoting about a second axis orthogonal to said first axis.

13. The apparatus of claim 12 wherein said driver circuit comprises at least one electrostatic plate spaced a selected distance from at least one of said pair of support anchors and an alternating voltage source connected between said at least one electrostatic plate and at least one of said pair of support anchors and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

14. The apparatus of claim 12 wherein said driver circuit comprises at least one portion of piezoelectric material having a first end and a second end, said portion of piezoelectric material bonded to at least one of said pair of support anchors and an alternating voltage source connected between said first end and said second end of said portion of piezoelectric material, and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

15. The apparatus of claim 12 wherein said driver circuit comprises a pair of electromagnetic coils, one end of said pair located on each side of said first axis and spaced from said functional surface portion, and an alternating voltage source connected across said pair of coils, and wherein the frequency of said alternating voltage source is substantially at said resonant frequency.

16. The apparatus of claim 12, and further comprising a pair of electromagnetic coils, one each of said pair located on each side of said second axis and spaced from said gimbals portion, and a voltage source connected across said pair of coils for selectively positioning said resonant functional surface in an orthogonal direction.

17. The apparatus of claim 1 wherein said functional surface portion further includes a first material thereon for interacting with a second material such that the combined mass of said functional surface position and said first material is changed.

18. The apparatus of claim 17 wherein said first material readily absorbs moisture.

19. The apparatus of claim 1 wherein said functional surface portion further includes a first plurality of materials at different locations on said functional surface, each one of said plurality for interacting with a second and different plurality of materials such that the combined mass of said functional surface and said first plurality of material is changed.

20. The apparatus of claim 7 wherein said functional surface portion further includes a first material thereon for interacting with a second material such that the combined mass of said functional surface position and said first material is changed.

21. The apparatus of claim 7 wherein said first material readily absorbs moisture.

22. The apparatus of claim 7 wherein said functional surface portion further includes a first plurality of materials at different locations on said functional surface, each one of said plurality for interacting with a second and different plurality of materials such that the combined mass of said functional surface and said first plurality of material is changed.

23. The apparatus of claim 12 wherein said functional surface portion further includes a first material thereon for interacting with a second material such that the combined mass of said functional surface position and said first material is changed.

24. The apparatus of claim 12 wherein said first material readily absorbs moisture.

25. The apparatus of claim 12 wherein said functional surface portion further includes a first plurality of materials at different locations on said functional surface, each one of said plurality for interacting with a second and different plurality of materials such that the combined mass of said functional surface and said first plurality of material is changed.

26. The apparatus of claim 1 and further including a measuring device for determining changes in said resonant frequency.

27. The apparatus of claim 7 and further including a measuring device for determining changes in said resonant frequency.

28. The apparatus of claim 12 and further including a measuring device for determining changes in said resonant frequency.

29. A method of providing a resonant pivoting motion to a functional surface comprising the steps of:

providing a functional surface pivotally attached to and integrally formed with a support portion by a first hinge arrangement, said functional surface having a resonant frequency at which said surface pivotally resonates about said hinge arrangement;

inertially coupling vibrational energy to said functional surface to cause said functional surface to pivotally resonate about said first hinge arrangement; and

detecting a change in said resonant frequency due to changes in the mass of said functional surface portion.

30. The method of claim 29 wherein said step of providing comprises the step of providing a functional surface integrally formed with and pivotally attached to support frame wherein a first portion of said support frame is also integrally formed with and attached to a support structure and said step of providing further comprising locating at least one electrostatic plate a selected distance form a second portion of said support frame and wherein said step of inertially coupling further comprises the step of connecting an alternating voltage between said electrostatic plate and said support frame to generate vibration in said support frame.

31. The method of claim 29 wherein said step of providing comprises the step of providing a functional surface integrally formed with and pivotally attached to a pair of support anchors and attaching a first portion of each of said pair of support anchors to a support structure, and said step of providing further comprising locating at least one electrostatic plate a selected distance from a second portion of at least one of said pair of support anchors and wherein said step of inertially coupling further comprises the step of connecting an alternating voltage to said electrostatic plate and at least one of said support anchors.

32. The method of claim 29 wherein said step of providing further comprises the steps of providing a functional surface integrally formed with and pivotally attached to a support frame and wherein a first portion of said support frame is attached to a support structure, bonding a portion of piezoelectric material having a first end and a second end to a second portion of said support frame, and wherein said step of inertially coupling further comprises connecting an alternating voltage to said first and said second end of said portion of piezoelectric material to generate vibrations in said support frame.

33. The method of claim 29 wherein said step of providing comprises the step of providing a functional surface integrally formed with and pivotally attached to a pair of support anchors and attaching a first portion of each of said pair of support anchors to a support structure, and said step of providing further comprising bonding a portion of piezoelectric material having a first end and a second end to a second portion of at least one of said support anchors and wherein said step of inertially coupling further comprises connecting an alternating voltage to said first end and said second end of said portion of piezoelectric material to generate vibration in said support frame.

34. The method of claim 29 wherein said step of providing further comprises the step of locating a pair of electromagnetic coils on each side of said first axis and spaced from said functional surface and wherein said step of inertially coupling further comprises connecting an alternating voltage across said pair of coils to generate vibration in said support frame.

35. The method of claim 29 wherein said step of providing comprises the steps of providing a functional surface integrally formed with and pivotally attached to a gimbals portion by a first hinge arrangement for pivoting about a first axis, and further comprising pivotally attaching said gimbals portion to an integrally formed support member by a second hinge arrangement for pivoting about a second axis orthogonal to said first axis.

36. The method of claim 35 and further comprising the step of pivoting said functional surface about said second axis to position said functional surface to a neutral position.

37. The method of claim 35 and further comprising the step of determining a change of the angular position of said functional surface portion due to said change in mass of said functional surface.

38. The method of claim 35 and further comprising the steps of including a first material on said functional surface on one of said second axis and including a second material on said functional surface on the other side of said axis, said first and second material interactive with third and fourth materials respectively, introducing one of said third and fourth materials to said first and second materials, and determining which of said third and fourth materials were introduced in response to a change in position of said functional surface due to a change in mass of said functional surface.